1. Field
The following description relates to a semiconductor device and a method of manufacturing the same, and to a semiconductor device manufactured by performing a Deep Trench Isolation (DTI) process on a semiconductor substrate after device structures such as a source, a drain, and a gate are formed on the semiconductor substrate by a silicide process and a method of manufacturing such a semiconductor device.
2. Description of Related Art
The development of electronic technology resulted in an increased demand for compact multi-functional electronic devices. For this reason, System on Chip (SoC) technology emerged. System on chip technology refers to a technology for implementing a single system that integrates a plurality of devices into a single chip. With the recent development of MEMS (Micro-Electro-Mechanical System) technology and NEMS (Nano-Electro-Mechanical System) technology, attempts to implement various devices as a single chip have taken place.
However, when a plurality of devices is integrated into a single substrate, interference is prone to occur between the devices. For instance, heat generated in driving of one device may transfer to another device through the substrate, and the heat may influence an operation of the second device. Thus, the interference between the devices may result in malfunction of the overall product.
In order to prevent the occurrence of malfunctions, a device isolation structure may be utilized to electrically isolate each of the devices on the single substrate from other devices.
Examples of technologies used for forming device isolation structures include a local oxidation of silicon (LOCOS) process, a trench isolation process and the like. The LOCOS process is an isolation method that involves masking a surface of a substrate with a relatively hard material such that a silicon nitride layer, and thermally growing a thick oxide layer in an opening of a mask. The trench isolation process is a method that involves forming a trench having an appropriate depth in a silicon substrate and filling the inside of the trench with an insulating film to electrically isolate devices from each other. Another kind of trench isolation process is the Deep Trench Isolation (DTI) process used for isolating wells.
Among the various technologies for forming device isolation structures, the deep trench isolation process is often applied to satisfy the requirement of high-integration of semiconductor devices. By using a deep trench isolation structure (DTI structure), it is possible to reduce a pitch of the transistor and to improve latch-up leading to a decrease in device characteristics due to current leakage and overcurrent. As a result, the DTI structure has characteristics suitable for reducing the size of chips and for improving the performance of devices.
In manufacturing processes for producing semiconductor devices in which a DTI structure is formed, the DTI process is generally performed before a process of forming a LOCOS or a shallow trench (STI) in the semiconductor substrate.
Incidentally, in manufacturing a semiconductor device such as a Lateral Double-diffused Metal Oxide Semiconductor (LDMOS) used as a high voltage power device, when the DTI process is performed before the LOCOS process or a process of forming a gate electrode, various issues may occur.
For example, in the manufacturing process of the semiconductor device, a plurality of annealing processes are performed as processes subsequent to the DTI process. Accordingly, the thermal stress resulting from the processes may affect a trench structure formed in the semiconductor substrate by the DTI process.
In order to reduce the problems resulting from the thermal stress, many additional processes for releasing the thermal stress may be performed, and the additional processes may in turn impose other challenges or problems.    Patent Document: Korean Laid-Open Publication No. 2011-0030356